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Friday, December 7, 2012

Fish Rescue Coral from Seaweed Attack

Photo Credit: Danielle Dixson

When corals are threatened by toxic seaweed they do what any
self-respecting sea creature does: they call for help. Scientists at the
Georgia Institute of Technology have been studying a coral reef in Figi. They discovered that when a toxic green seaweed gets on the corals, the corals send
chemical signals to Gobis. The inch-long fish respond by nibbling off the
seaweed.

The scientists did a number of experiments. In one they
moved filaments of a toxic seaweed onto coral. Within a few minutes, two
species of gobies moved in and began trimming off the seaweed.

In corals where gobies lived, the fish mowed off the seaweed
and reduced seaweed damage significantly. Corals without gobies were damaged by
the seaweed. The scientists analyzed the fish digestive systems and learned
that one of the gobi species actually eats the seaweed. The other fish
apparently bites it off and leaves it.

For the fish that eat the seaweed, the toxic chemicals may
make the fish less attractive to predators. In exchange for cleaning the coral,
the fish receive shelter. It’s a win-win situation: the fish protect the coral
and in return they get a place to live.